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Spinel oxides are promising low-cost catalysts with manifold and controllable physicochemical properties. Trial and error strategies cannot achieve the effective screening of high-performance spinel catalysts. Therefore, unraveling the structure–performance relationship is the foundation for their rational design. Herein, the effects of cations in tetrahedral and octahedral sites on the electronic structures of spinels were systematically investigated using GGA + U calculations based on ACr2O4 (A = Mn, Fe, Co, Ni, and Zn) and Zn/LiB2O4 (B = Cr, Mn, Fe, Co and Ni). The results indicate that the octahedrally coordinated B cations have notable influence on the electronic structures of spinels. The Jahn–Teller active ions Fe2+, Ni2+, Mn3+, Ni3+, Cr4+ and Fe4+ can remarkably reduce the band gaps of spinels and even change their electroconductibilities. These results will provide theoretical insights into the electronic properties of 3d transition metal spinels.

A peroxidase catalyzes the oxidation of a substrate with a peroxide. The search for peroxidase-like and other enzyme-like nanomaterials (called nanozymes) mainly relies on trial-and-error strategies, due to the lack of predictive descriptors. To fill this gap, here we investigate the occupancy of eg orbitals as a possible descriptor for the peroxidase-like activity of transition metal oxide (including perovskite oxide) nanozymes. Both experimental measurements and density functional theory calculations reveal a volcano relationship between the eg occupancy and nanozymes’ activity, with the highest peroxidase-like activities corresponding to eg occupancies of ~1.2. LaNiO3-δ, optimized based on the eg occupancy, exhibits an activity one to two orders of magnitude higher than that of other representative peroxidase-like nanozymes. This study shows that the eg occupancy is a predictive descriptor to guide the design of peroxidase-like nanozymes; in addition, it provides detailed insight into the catalytic mechanism of peroxidase-like nanozymes.

Nanozymes, the enzyme-mimicking nanomaterials, have been developed to overcome the low stability and high cost of natural enzymes. Unlike highly active and specific enzymes, however, the catalytic ...

The structural transformation and mechanical properties of fullerenes under high pressure have attracted a significant interest. However, the research data on the large-cage endohedral metallofulle...

Enzyme-mediated activation of prodrug in tumor cells is an attractive strategy for targeted cancer therapy. Of note, natural peroxidase and indole-3-acetic acid (IAA) have been shown as a promising enzyme-prodrug combination. However, insufficient endogenous peroxidase activity and the difficulty in selectively expressing exogenous peroxidase in tumor cells have severely limited its antitumor efficiency. The discovery of nanomaterials with peroxidase-like activity (nanozyme), particularly the metal-free nanozymes that possesses high stability and good biocompatibility, bring a new opportunity to overcome these challenges. Here, under the guidance of theoretical calculations, we developed a metal-free phosphorous and nitrogen dual-doped porous hollow carbon sphere nanozyme (PNCNzyme) with robust peroxidase-like activity in acidic environment. Based on this metal-free nanozyme, we developed a nanozyme-IAA activation strategy that activated IAA to produce abundant ROS and trigger tumor cell apoptosis. We also introduced folate (FA) onto the nanozyme to enhance its tumor targeting and endocytosis efficacy by tumor cells. Upon administrated to mice, the FA-PNCNzymes@IAA effectively accumulated in the xenografts derived from cervical cancer cells, catalyzed the production of ROS, and induced apoptosis. Taken together, these data demonstrate that the nanozyme-IAA combination is an effective enzyme-prodrug activation strategy for tumor targeted catalytic therapy.

Highest occupied molecular orbital–lowest unoccupied molecular orbital (H-L) energy gaps govern the chemical stabilities of molecules. Molecules with larger H-L gaps are more inert to chemical reactions and thus more experimentally separable. In this sense, H-L gaps play a more important role than energies of formation in determining the structures of the fullerenols that can be experimentally isolated. However, previous structural predictions for fullerenols are mainly based on energies. Recently, we proposed a rule of chemical stability for multiple addition products of fullerenes and endohedral metallofullerenes. In this study, we implement this rule into a computer program and use it to automatically determine large-energy-gap structures for C60 and C82 fullerenols. C60(OH)n (n = 12–48) and C2v(9)-C82(OH)x (x = 14–58) fullerenols have been studied using this program. All the structures determined have H-L gaps larger than those predicted previously. Some of the structures simultaneously have even more...

The empirical Clar model describes the π-electronic configurations for polycyclic aromatic hydrocarbons with closed-shell singlet ground states. However, it is not applicable to nanographenes (NGs), which usually have open-shell ground states. To model the π-electronic configurations of NGs, a new structural unit, radical half-sextet, was introduced. The modified Clar model can profoundly depict the π-electronic configurations for both nonmagnetic and magnetic NGs and thus can be used as the general model for NGs. The new model can precisely predict the favorable reaction patterns for NGs and can profoundly explain the already-known reactions of NGs.

The Lewis base stabilized borylenes and boryls are used to construct one dimension nanowires. Using the Lewis base (L) to coordinate sp2 borons, we constructed B5L5− cyclic compounds with six π-electrons. Then, using B5L5 and transition metals as building units, we further constructed half-sandwich and sandwich compounds. We found that the B5(CO)5 is the η5-ligand with stronger bonding affinity with Mn and Fe than the traditional cyclopentadiene. The calculated electronic band structures suggested that the constructed nanowire [VB5(CO)5FeB5(CO)5]∞ is an organic half-metal. The results may cast light on the future synthesis of boron-based metallocene-like molecules.

Tumor necrosis factor-α (TNF-α) is a cell signalling protein involved in systemic inflammation in infectious and other malignant diseases. Physiologically, it plays an important role in regulating host defence, but its overexpression can lead to serious illnesses including cancer, autoimmune disease and inflammatory disease. Gadolinium-based metallofullerenols, e.g., Gd@C82(OH) x (x ≈ 22), are well known for their abundant biological activities with low toxicity experimentally and theoretically; however, their activity in direct TNF-α inhibition has not been explored. In this work, we investigated the inhibiting effects of four types of fullerene-based ligands: fullerenes, fullerenols, metallofullerenes, and metallofullerenols. We reported previously that fullerenes, metallofullerenes and their hydroxylated derivatives (fullerenols) can reside in the same pocket of the TNF-α dimer as that of SPD304-a known inhibitor of TNF-α [He et al. (2005) Science 310:1022, 18]. Ligand docking and binding free energy calculations suggest that, with a similar nonpolar interaction dominated binding pattern, the fullerene-based ligands, C60, C60(OH)12, Gd@C60, C82, C82(OH)12, Gd@C82, Gd@C82(OH)13 and Gd@C82(OH)21, have larger affinity than currently known inhibitors, and could be used to design novel inhibitors of TNF-α in the future. Graphical Abstract Fullerene-material/TNF-α.